code: def test_str_cat_categorical(
      index_or_series, dtype_caller, dtype_target, sep, infer_string
  ):
      box = index_or_series
  
      with option_context("future.infer_string", infer_string):
          s = Index(["a", "a", "b", "a"], dtype=dtype_caller)
          s = s if box == Index else Series(s, index=s, dtype=s.dtype)
          t = Index(["b", "a", "b", "c"], dtype=dtype_target)
  
          expected = Index(
              ["ab", "aa", "bb", "ac"],
              dtype=object if dtype_caller == "object" else None,
          )
          expected = (
              expected
              if box == Index
              else Series(
                  expected,
                  index=Index(s, dtype=dtype_caller),
                  dtype=expected.dtype,
              )
          )
  
          # Series/Index with unaligned Index -> t.values
          result = s.str.cat(t.values, sep=sep)
          tm.assert_equal(result, expected)
  
          # Series/Index with Series having matching Index
          t = Series(t.values, index=Index(s, dtype=dtype_caller))
          result = s.str.cat(t, sep=sep)
          tm.assert_equal(result, expected)
  
          # Series/Index with Series.values
          result = s.str.cat(t.values, sep=sep)
          tm.assert_equal(result, expected)
  
          # Series/Index with Series having different Index
          t = Series(t.values, index=t.values)
          expected = Index(
              ["aa", "aa", "bb", "bb", "aa"],
              dtype=object if dtype_caller == "object" else None,
          )
          dtype = (
              object
              if dtype_caller == "object"
              else s.dtype.categories.dtype
          )
          expected = (
              expected
              if box == Index
              else Series(
                  expected,
                  index=Index(expected.str[:1], dtype=dtype),
                  dtype=expected.dtype,
              )
          )
  
          result = s.str.cat(t, sep=sep)
          tm.assert_equal(result, expected)
  
file_path: pandas/pandas/tests/strings/test_cat.py
imports: import re
  import numpy
  import pytest
  import pandas.util._test_decorators
  from pandas import DataFrame, Index, MultiIndex, Series, _testing, concat, option_context
label_desc: Use image node_id 5 for calling a global function with example usage: test_str_cat_categorical(index_or_series, dtype_caller, dtype_target, sep, infer_string) without return types